The overall goal of this project is to understand how a cell coordinates the global expression of its genetic repertoire in response to environmental stimuli. Using bacteria (E. coli and S. typhimurium) as models, we have focused on events regulated by an intracellular hormone-like compound guanosine 3',5'-bispyrophosphate (ppGpp). We have studied both positive and negative regulation of operons regulated by ppGpp (histidine operon and ribosomal RNA operon). As a model for eukaryotic cells, we have initiated studies with a rat adrenal cortical carcinoma cell line that retains partial glucocorticoid hormone responsiveness to adrenal corticotropic hormone (ACTH). Our major findings are: 1. The regions surrounding ribosomal RNA tandem promoters, distinct from the promoters themselves, play significant roles in regulating the differential expression of promoters. 2. Anti-termination of ribosomal RNA operon transcripts has been shown analogous to phage lambda anti-termination both structurally and functionally yet the mechanisms are distinguished by lambda N gene dependence. 3. The dependence of his operon expression on ppGpp has been characterized genetically and has been exploited to yield mutants in ribosome dependent ppGpp synthesis (relA), in ppGpp degradation (spoT, and in more interesting but as yet uncharacterized new loci. 4. Messenger RNA from both normal rat adrenals and an adrenal tumor cell line has been isolated and translated in vitro. The tumor cell line has two unusually abundant ethidium staining RNA regions at about 2 Kb and about 6.5 Kb. A cDNA library has been prepared from the tumor cell line.